It is known as disclosed for example in the Milton L. Benjamin et al U.S. Pat. No. 3,743,307, granted July 3, 1973, to provide a spring actuated chuck in which a clamping and releasing nut assembly is released for spring actuation upon insertion of the shank of a tool adapter into the socket of a holder to clamp the adapter to the holder, the adapter being released from the holder by rotation of the nut in the opposite direction against spring pressure to a latched position whereat the adapter is released for axial withdrawal from the holder. In this form of spring actuated chuck the threads of the nut and also a latching groove therein are exposed to fine chips and coolant when a tool mounted in the adapter is performing a cutting operation thereby necessitating a strong spring to assure desired spring actuation of the nut and to assure proper latching when the adapter is to be released from the holder. Generally the springs in known spring actuated chucks are so strong that the increased clamping force due to the spring and to the increased inertia of the nut assembly and vibration requires the use of a wrench to rotate the nut back to its latched unlocking position to release the adapter for removal and replacement.
Furthermore, in known spring actuated chucks, the ejector and clamping lugs generally rotate in unison whereby the ejector lug or lugs may have frictional sliding engagement with the flange of the adapter during the adapter clamping operation. Moreover, during the releasing operation, relatively high contact pressures are entailed between the circumferentially narrow ejector lug or lugs in sliding frictional engagement with the flange of the adapter.